1. Field of the Invention
The present invention relates to three-dimensional image displays.
2. Background Art
Images may be generated for display in various forms. For instance, television (TV) is a widely used telecommunication medium for transmitting and displaying images in monochromatic (“black and white”) or color form. Conventionally, images are provided in analog form and are displayed by display devices in two-dimensions. More recently, images are being provided in digital form for display in two-dimensions on display devices having improved resolution (e.g., “high definition” or “HD”). Even more recently, images capable of being displayed in three-dimensions are being generated.
Conventional displays may use a variety of techniques to achieve three-dimensional image viewing functionality. For example, various types of glasses have been developed that may be worn by users to view three-dimensional images displayed by a conventional display. Examples of such glasses include glasses that utilize color filters or polarized filters. In each case, the lenses of the glasses pass two-dimensional images of differing perspective to the user's left and right eyes. The images are combined in the visual center of the brain of the user to be perceived as a three-dimensional image. In another example, synchronized left eye, right eye LCD (liquid crystal display) shutter glasses may be used with conventional two-dimensional displays to create a three-dimensional viewing illusion. In still another example, LCD display glasses are being used to display three-dimensional images to a user. The lenses of the LCD display glasses include corresponding displays that provide images of differing perspective to the user's eyes, to be perceived by the user as three-dimensional.
Problems exist with such techniques for viewing three-dimensional images. For instance, persons that use such displays and systems to view three-dimensional images may suffer from headaches, eyestrain, and/or nausea after long exposure. Furthermore, some content, such as two-dimensional text, may be more difficult to read and interpret when displayed three-dimensionally. To address these problems, some manufacturers have created display devices that may be toggled between three-dimensional viewing and two-dimensional viewing. A display device of this type may be switched to a three-dimensional mode for viewing of three-dimensional images, and may be switched to a two-dimensional mode for viewing of two-dimensional images (and/or to provide a respite from the viewing of three-dimensional images).
A parallax barrier is another example of a device that enables images to be displayed in three-dimensions. A parallax barrier includes of a layer of material with a series of precision slits. The parallax barrier is placed proximal to a display so that a user's eyes each see a different set of pixels to create a sense of depth through parallax. A disadvantage of parallax barriers is that the viewer must be positioned in a well-defined location in order to experience the three-dimensional effect. If the viewer moves his/her eyes away from this “sweet spot,” image flipping and/or exacerbation of the eyestrain, headaches and nausea that may be associated with prolonged three-dimensional image viewing may result. Conventional three-dimensional displays that utilize parallax barriers are also constrained in that the displays must be entirely in a two-dimensional image mode or a three-dimensional image mode at any time.